module Test(g) where

data B = TT | FF

g TT TT x1 y1 x2 y2 = TT
g x0 y0 TT TT x2 y2 = TT
g x0 y0 x1 y1 TT TT = TT
g TT FF x1 y1 x2 y2 = TT
g x0 y0 TT FF x2 y2 = TT
g x0 y0 x1 y1 TT FF = TT
g FF y0 FF y1 FF y2 = TT